4-(4-Chlorophenyl)-5-imino-1,3-diphenyl-1,4-dihydropyrazolo[4',3':5,6]pyrano[2,3-d]pyrimidin-6(5H)-amine 4-(4-Chlorophenyl)-5-imino-1,3-diphenyl-1,4-dihydropyrazolo[4',3':5,6]pyrano[2,3-d]pyrimidin-6(5H)-ylamine AIDS-151331 AIDS151331 NSC691418